CAMBRIDGE, Mass. — Sen. Elizabeth Warren jumped into the 2020 presidential campaign Monday, offering a message of economic populism as she became the best-known Democratic candidate yet to enter what is expected to be a crowded race.

Warren’s announcement that she was establishing an exploratory committee — the legal precursor to a run — came as other candidates, including several of her fellow senators, made final preparations for their own announcements, some of which are expected in days.

It made no mention of a recent Warren stumble: her October decision to release results of a DNA test that said she probably had a distant Native American ancestor. The move had been meant to stifle Trump’s criticism of her but only engendered more mockery from him, while also angering Democrats, particularly minorities who objected to her defining ethnicity via a test.

While the race for the Democratic nomination is only starting, even Warren’s supporters acknowledge that she has lost ground in the last few months, both by her own hand and because the November midterm elections redefined Democratic success with candidates who were in many cases a generation younger.